1. Field of the Invention
The present invention relates to a method for manufacturing cold bonded pellets.
2. Description of the Prior Art
As the publicly known prior art methods for manufacturing cold bonded pellets, two curing methods are pointed out. The one is an atmospheric curing method, and the other is a curing method which utilizes mainly a hydration bond.
According to the first method, fine iron ore, powdery coke and cement are mixed with each other, green pellets obtained by pelletizing the mixture thereof are stacked up in a yard and cured in the atmosphere. In this method, equipment necessary for the curing of the green pellets is only a yard of a predetermined area, but there is a problem such that it takes around ten days for the curing.
According to the second method, green pellets are charged into a shaft, a curing gas containing 25 vol. % CO.sub.2, 25 vol. % H.sub.2 O and 50 vol. % N.sub.2 is circulated in the shaft to cure the green pellets by a hydration reaction, and the green pellets cured are charged into a second shaft to be dried. In the second method, time for the curing of the green pellets can be reduced to around ten hours, but a number of shafts should be prepared to manufacture a great amount of cold bonded pellets.